• 대한의용생체공학회:의공학회지
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• 제29권4호
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• pp.286-294
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• 2008

This work investigates the characteristics of brain interactions of experienced Zen-Buddhist practitioners by obtaining multichannel EEG (electroencephalogram) data. Brain interactions were compared among three phases-40-minute meditation (M), 5-minute Chakra-focusing practice (Z) and rest with closed eyes (R). The similarity index S, developed in nonlinear dynamical system theory, was employed to measure the degree of possibly asymmetric coupling. Meditators exhibited, overall, stronger interactions among multiple cortical areas in meditation stages M and Z than in the R state. This enhancement was greater in the M stage when the meditator was accompanied by a thought-free and fully consciousness state. In the high-frequency band (>13Hz), the interdependence was also higher in both meditation stages than at baseline rest. However, the interaction strength, especially in the posterior regions, was greatest in the Z stage, which involved internal attention. Few electrode pairs were observed with significant pair-wise asymmetry in the Z state. The similarity is a possible characteristic of dense reciprocal and strong mutual interactions between multiple cortical areas during meditation - especially in the Z state in the high-frequency band. These results demonstrate that profound Zen meditation induces various dynamic states in different phases of meditation, possibly reflected by nonlinear interdependence measure.

• 식물분류학회지
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• 제50권3호
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• pp.333-342
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• 2020

Despite poorly documented species delimitation and unresolved taxonomic nomenclature, four species of Symplocos (S. coreana, S purnifolia, S sawafutagi, and S. tanakana) have been described in Korea. In this study, we carried a comparative wood anatomy analysis of all four species of Korean Symplocos to understand the wood anatomical variations among them. The results of this study indicated that Korean Symplocos are comparatively indistinguishable in terms of their qualitative wood features, except for exclusively uniseriate rays present in S. purnifolia instead of uniseriate to multiseriate in other three species. Nevertheless, differences are noticed in quantitative wood variables such as the vessel density, vessel size, and ray density. The vessel density of S. purnifolia is more than twice as high as those of S. sawafutagi and S. tanakana. In contrast, the vessel circumference and diameter on both plants of S. sawafutagi and S. tanakana is nearly twice as large as those of S. purnifolia. Symplocos coreana has characteristic intermediacy between these two groups in terms of vessel features and is closer to S. purnifolia in terms of its ray density level. A cluster analysis based on a paired group (unweighted pair-group method with the arithmetic mean, UPGMA) algorithm using the Euclidean similarity index clearly differentiates S. purnifolia from the remaining species, representing the first branch of the phenogram.

• 수산해양교육연구
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• 제27권1호
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• pp.49-62
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• 2015

As methods reducing damages by jellyfish which enter the coastal areas of Korea, attaching cutting devices to towing nets of otter trawls or pair trawls and/or using a canvas type of cutting nets of small fishing boats have been widely utilized. In order to reduce shut-down damages of power plants in coastal areas due to the mass influx of marine organisms including jellyfish, a possible improvement of the traveling water screen system and various jellyfish influx blocking devices were suggested in this study. The results could be utilized as an important index for reducing damages by jellyfish bloom which cause on a massive scale in summer in Korea.

• 한국물환경학회지
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• 제32권1호
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• pp.80-88
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• 2016

The main purpose of this study was to derive managerial priority for pollutants in drinking water using the Delphi technique and analytic hierarchy process (AHP) method. We collected fundamental existing items based on a literature review for water pollutants, and deduced a total of 36 sub-items from nine core sectors, as follows: organic matter; inorganic substances; pathogenic organisms; chemicals; heavy metals; radioactive substances; sediment deposits; heat; and oil, and then conducted the first round of an expert study to ensure that objective indicators properly evaluate major issues for management of for drinking water quality. In the following round, the necessity and importance assessments of adjusted items were implemented using a content validity ratio index. Finally, items modified by Delphi surveys were applied to AHP. We computed weighted values by pair-wise comparison of sub-items and each of five sectors modified by the second round. According to the results of AHP, the managerial priority for pollutants in drinking water was as follows; while heavy metal placed first in importance, pathogenic organisms came second, followed by inorganic substances, organic matter and chemical substances from the sector perspective.

• Fisheries and Aquatic Sciences
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• 제8권1호
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• pp.17-26
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• 2005

The ultrastructure of germ cells during spermatogenesis and the structural changes in the epithelial cells of the seminal vesicle with testicular development in male Neptunea (Barbitonia) arthritica cumingii were investigated monthly based on electron microscopic and histologic observations. N. arthritica cumingii (Gastropod: Buccinidae) undergoes internal fertilization and possesses a modified type of spermatozoon, which is approximately 20$\mu$m long. The axoneme of the tail flagellum consists of nine peripheral pairs of microtubules and one central pair. Many spermatozoa occur in the acini of the testis in the ripe stage and are transported to the seminal vesicles in the accumulating phase. In males, the monthly gonadosomatic index began to increase in September and reached a maximum in February. Subsequently, it decreased rapidly after April. The testis of this species can be classified into four developmental stages: the active (August to September), ripe (October to July), copulation (April to July), and recovery (July to August) stages. Structural changes in the epithelial cells of the seminal vesicles of this species could be classified into three phases: (1) S-I (resting), (2) S-II (accumulating), and (3) S-III (spent) phases. The morphology and structure of the epithelial cells of the seminal vesicle differed in each phase; the cells were cuboidal, squamous, or columnar in the resting, accumulating, or spent phases, respectively.

• Archives of Pharmacal Research
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• 제27권12호
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• pp.1270-1274
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• 2004

Random amplified polymorphic DNA (RAPD) analysis was used to determine the genetic relationships among seventeen species of the Acanthopanax species. The DNA isolated from the leaves of the samples was used as template in polymerase chain reaction (PCR) with twenty random decamer primers in order to distinguish plant subspecies at the level of their genomes. The RAPD patterns were compared by calculating pairwise distances using Dice similarity index, and produced to the genetic similarity dendrogram by unweighted pair-group method arithmetic averaged (UPGMA) analysis, showing three groups; a major cluster(twelve species), minor cluster (4 species) and single-clustering species. The results of RAPD were compatible with the morphological classification, as well as the chemotaxonomic classification of the Acanthopanax species. The Acanthopanax species containing 3,4-seco-lupane type triterpene compounds in their leaves corresponded to the major cluster, another species having oleanane or normal lupane type constituents to minor clusters, and one species not containing triterpenoidal compound to single-cluster.

• Earthquakes and Structures
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• 제9권5호
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• pp.1091-1114
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• 2015

The adequacy of a number of advanced earthquake Intensity Measures (IMs) to predict the structural damage of earthquake resistant 3D R/C buildings is investigated in the present paper. To achieve this purpose three symmetric in plan and three asymmetric 5-storey R/C buildings are analyzed by nonlinear time history analysis using 74 bidirectional earthquake records. The two horizontal accelerograms of each ground motion are applied along the structural axes of the buildings and the structural damage is expressed in terms of the maximum and average interstorey drift as well as the overall structural damage index. For each individual pair of accelerograms the values of the aforementioned seismic damage measures are determined. Then, they are correlated with several strong motion scalar IMs that take into account both earthquake and structural characteristics. The research identified certain IMs which exhibit strong correlation with the seismic damage measures of the studied buildings. However, the degree of correlation between IMs and the seismic damage depends on the damage measure adopted. Furthermore, it is confirmed that the widely used spectral acceleration at the fundamental period of the structure is a relatively good IM for medium rise R/C buildings that possess small structural eccentricity.

• 한국정보과학회논문지:데이타베이스
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• 제28권3호
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• pp.373-383
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• 2001

거리조인은 두 공간 데이터 집합 사이의 데이터쌍을 거리 상 가까운 순으로 검색하는 공간조인이다. 본 논문에서는 [1]에서 제시한 적응식 다단계 거리 조인 기법을 최적화하기 위한 기법들을 제안한다. 첫째, 평면 스위핑 축 선택을 위해 사용되는 스위핑 인덱스 공식을 최적화한다. 둘째, 노드쌍을 관리하는데 사용한 메인큐의 성능 향상을 위하여 노드쌍의 최대 거리값을 큐의 2차 우선 순위로 적용하는 기법을 제안한다. 또한, 균등 분포 및 비균등 분포 가정하의 한계 거리값 예측 기법의 장단점을 비교한다. 실험 결과는 제안하는 기법들을 통하여 알고리즘의 성능이 CPU 비용과 I/O 비용 면에서 크게 향상되었음을 보여준다.

• 농촌계획
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• 제15권1호
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• pp.47-59
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• 2009

The aim of this study is to analyze the green-tourism centrality considering spatial interaction using Gravity Model and social network method. The degree centrality and prestige centrality were applied as green-tourism centrality index. The rural amenity resources and human resources were counted as attraction factors, and a distance among villages was used as friction factor in gravity model. The weights of rural tourism amenity resources were calculated using the analytic hierarchy process(AHP) method and applied to evaluate green-tourism potentiality. The distance was measured with the shortest path among villages using geographic information system(GIS) network analysis. The spatial interaction from gravity model were employed as link weights between nodal points; a pair villages. Using the spatial interaction, the degree-centrality and prestige-centrality indices were calculated by social network analysis and demonstrated possibility of developing integrated green-tourism region centered on high centrality villages.

• 한국자기공명학회논문지
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• 제23권1호
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• pp.12-19
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• 2019

A former study has shown that the spin-lattice relaxation time ($T_1$) in cancerous prostate tissue had enhanced contrast at an ultra-low magnetic field, $132{\mu}T$. To study the field dependence and the origin of the contrast we measured $T_1$ in pairs of ex-vivo prostate tissues at the Earth's magnetic field. A portable and coil-based nuclear magnetic resonance (NMR) system was adopted for $T_1$ measurements at $40{\mu}T$. The $T_1$ contrast, ${\delta}=1-T_1$ (more cancer)/$T_1$(less cancer), was calculated from each pair. Additionally, we performed pathological examinations such as Gleason's score, cell proliferation index, and micro-vessel density (MVD), to quantify correlations between the pathological parameters and $T_1$ of the cancerous prostate tissues.